DE3127193A1 - Process for preparing N-cyclohexylbenzothiazole-2-sulphenamide - Google Patents

Abstract

The invention relates to a process for preparing N-cyclohexylbenzothiazole-2-sulphenamide. The process is based on 2-mercaptobenzothiazole being initially reacted with excess cyclohexylamine and the resulting solution of the cyclohexylamine salt then being oxidised with an oxidising agent, e.g. with sodium hypochlorite. The by-products of the oxidation are separated off, for example by filtration. The 2-mercaptobenzothiazole can be employed in the form of a crude reaction product which arises as waste in the industrial high-pressure reaction of aniline, carbon disulphide and sulphur. The process gives high yields and a high degree of product purity and is simple to carry out on an industrial scale.

Description

Chemicke zävody Juraja Dimitrova, närodny podnik

Bratislava, CSSR

Process for the preparation of N-cyclohexylbenzothiazole-2-sulfenamide

The invention relates to a process for the preparation of N-cyclohexylbenzothiazole-2-sulfenainide by reaction of 2-mercaptobenzothiazole and cyclohexylamine with one Oxidizing agent. N-Cyclohexy Iben / .othlazol -2-fiulfonam i d is used technically as a safe accelerator in rubber vulcanization.

N-Cyclohexylbenzothiazole-2-sulfenamide is conventionally used by oxidation of the cyclohexylamine salt of 2-mercaptobenzothiazole with a solution of Sodium hypochlorite or hydrogen peroxide

233- (S9924) -SF-Bk

·· ♦ ■

- SH

CSNH-

manufactured.

The cyclohexylamine salt of 2-mercaptobenzothiazole is made from the corresponding sodium / calcium or ammonium salt accessible. When cleaning the raw melt, 2-mercaptobenzothiazole is obtained in the form of these salts.

A process for the preparation of the sodium salt is described in CS-PS 114 693, US-PSs 2 191 657, 2 268 467 and 2,762,814, DE-PS 855 564, DE-AS 1 940 364 and GB-PS 642 597, 665 668 and 1 106 577, the production of the calcium salt in CS-PS 113 006 and DE-AS .1 940 364 and the production of the ammonium salt described in the CS copyright certificate 184 052.

All procedures are based on the same principle that an aqueous solution of the corresponding 2-mercaptobenzothiazole salt added a prescribed amount of cyclohexylamine and the resulting Solution or suspension of the cyclohexylamine salt of 2-mercaptobenzothiazole with a suitable oxidizing agent is treated.

The direct preparation of such sulfenamides from the amine salt of 2-mercaptobenzothiazole is in the U.S. Patents 2,339,002, 2,772,279 and 3,144,652; British Patents 452,044, 655,668, 1,16,577, 519,617 and 1,289,407, U.S. Patents Nos DE-PS 615 580, DE-AS 2 056 762, FR-PSs 852 118, 950 693 and 1 549 002 and the JA patent applications 74-110 664 and 74-134 674 are given.

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These conventional procedures are in numerous Cases afflicted with considerable disadvantages. The inorganic bases used are in the form of salts into the sewage over; when using the calcium salt of 2-mercaptobenzothiazole also accumulate soiled calcium sludge, with the product through acidic laundry must be freed from the insoluble calcium compounds. If, on the other hand, started from the ammonium salt corresponding production systems become more complex.

Possess sulfenamides made from the sodium salt also not the desired quality and must has therefore been subjected to cleaning, for example from FR-PS 2 056 749, DE-AS 1 940 365, the GB-PS 756 464 and US-PS 2,762,814 shows what with. associated increased losses and higher amounts of wastewater. is.

The invention is based on the finding that N-Cyc 1 ohexy! Benzot hia '/. Oi-2-fiul fenamid mil; high purity 'by reacting 2-mercaptobenzothiazole, cyclohexylamine and sodium hypochlorite or hydrogen peroxide can be produced.

The invention is accordingly based on the object of a novel process for the preparation of N-cyclohexylbenzothiazole-2-sulfenamide indicate that without the disadvantages of the previous method in a simple manner and leads to a pure product with high yield.

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The problem is solved according to the claims.

In the process according to the invention, 2-mercaptobenzothiazole is first used reacted with excess cyclohexylamine, 1.5 to 5 mol and preferably 2.5 mol of cyclohexylamine per mole of 2-mercaptobenzothiazole are used, whereupon the resulting solution of the cyclohexylamine salt of 2-mercaptobenzothiazole then with the oxidizing agent

will

20 b.is 70 ⁰ C and 45 ⁰ C, preferably oxidized / and the by-products of the oxidation are separated, for example by filtration.

The 2-mercaptobenzothiazole can be used in the form of a crude product for the reaction, which in the High-pressure reaction of aniline, carbon disulfide and sulfur arises, whereby it may be previously of volatile components was released; however, this separation is not absolutely necessary.

The process according to the invention leads to high yields and high purity of the N-cyclohexylbenzothiazole-2-sulfenamide obtained, At the same time, the process is simplified as much as possible, since the cyclohexylainine salt of 2-mercaptobenzothiazole in the same reactor without isolation to give N-cyclohexylbenzothiazole-2-sulfenamide is oxidized. The inventive method is also advantageous in that significantly less waste products

and wastewater accumulate, which is ecologically of special bodoutung ' is.

The process according to the invention for the preparation of N-cyclohexylbenzothiazole-2-sulfenamide is described below

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explained in more detail using examples.

example 1

In a 500 ml four-necked flask with a speed stirrer! Thermometer, reflux condenser and dropping funnel were ■) ... 118.8 g (0.6 mol) of 50% aqueous cyclohexylamine and 34.8 g (0.2 mol) of technical 96% 2-MCrCaPLObGnZoLhLaZOl. The contents of the flask were ^{heated to 85 °} C. while mixing, resulting in a solution of the cyclohexylamine salt of 2-mercaptobenzothiazole, which was then cooled ^{to 45 ° C.}

■ '■}

^{110 ml of sodium hypochlorite solution (16.7 g Cl + 1/100} ml) were added evenly from the dropping funnel over a period of 60 minutes. After cooling, the temperature was kept at 42 to 45 ^° C. After about 3/4 of the volume of the sodium hypochlorite solution had been added, a crystalline product began to separate out from the reaction mixture. After completion of the addition of the Natriumhypo- ¹ chlorite solution, the reaction mixture after 30 min was allowed to react and then cooled to 20 ⁰ C. The crystalline product was separated off by filtration and washed on the filter with 1000 ml of 10% strength cyclohexylamine and then with 700 ml of water.

The wet product was dried to constant weight.

The yield of N-cyclohexylbenzothiazole-2-sulfen amide was 48.2 g (91.2% of theory).

N AC -10 (.-. Rg

F. 101.5 to 102 ⁰ C.

Sulfenamide content 99.7% by weight, insoluble remainder 0.14% by weight.

. The mother liquor and the first wash water (two-phase system) were combined and distilled under normal pressure (0.1 MPa). There were 94.4 g of the azeotropic Mixtures of cyclohexylamine with water obtained after supplementing with fresh cyclohexylamine in the Process was returned. The yield was 94.2% of theory. Th., Based on the amount of cyclohexylamine used .

Example 2

The procedure was as in Example 1, except that 79.2 g (0.4 mol) of 50% strength cyclohexylamine were used.

48.6 g of product were isolated (yield 91.9% of theory).

F. 100 - 102 ⁰ C.

Sulfenamide content 98.2% by weight, insoluble remainder 0.25% by weight.

Example 3

The procedure was as in Example 1, except that 200 g (1.0 mol) of 50% strength cyclohexylamine were used

45.1 g of product were isolated (yield 85.3%

d. Th.) "

SUBMITTED

M.p. 102 ⁰ C

Sulfenamide content 99.9% by weight
insoluble remainder 0.1% by weight.

Example 4

The procedure was as in Example 1, but the temperature was 30 ^° C. during the addition of the sodium hypochlorite solution.

47.2 g of product were isolated (yield 98.2% of theory.

F. 99-101 ⁰ C '_

Sulfenamide content 98.9% by weight "- ··· '> π insoluble remainder 0.9% by weight.

Example 5

The procedure was as in Example 1, but the temperature was 70 ^° C. during the addition of the sodium hypochlorite solution.

46.2 g of product were isolated (yield 80.55% of theory).

P, from 101.5 to 102 ⁰ C.

Sulfenamide content 99.5% by weight, insoluble remainder 0.15% by weight.

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Example 6

The procedure was as in Example 1, but 36.3 g of a 92.0% crude reaction product of the High pressure reaction of aniline, carbon disulfide and Sulfur were used.

The yield of the product was 48.0 g (90.8% of theory)

F. 101 to 103.4 ⁰ C

Sulfenamide content 99.3% by weight, insoluble remainder 0.14% by weight.

QeüruJert

Example 7

The procedure was as in Example 1, except that 38.8 g of an 86.3% strength crude reaction product from the high pressure reaction of aniline, carbon disulfide and sulfur were used.

The yield of product was 46.4 g (87.7% of theory)

M.p. 100-102 ^° C

Sulfenamide content 98.8% by weight, insoluble remainder 0.15% by weight.

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Example 8

The procedure was as in Example 1, but

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for oxidation 102.5 ml sodium hypochlorite solution (16.7 g Cl / 100 ml) were used.

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The yield of product was 45.3 g (85.7% of theory..) F. '100-101 ⁰ C.

Sulfenamide content 99.8% by weight

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insoluble remainder 0.17% by weight. ■ "'■ ■

Example 9

The procedure was as in Example 1, but instead of sodium hypochlorite as the oxidizing agent g of 5% hydrogen peroxide were used.

The yield of product was 46.1 g (87.1% of theory)

F. 101-102 ⁰ C.

Sulfenamide content 99.4% by weight, insoluble remainder 0.13% by weight.

Example 10

The procedure was as in Example 6, except that 184 g of 5% strength hydrogen peroxide were used for the oxidation became.

The yield of product was 46.0 g (87.0% of theory)

F, 101 to 103 ⁰ C

Sulfenamide content 99.2% by weight, insoluble remainder 0.10% by weight.

The procedure was as in Example 7, except that 184 g of 5% strength hydrogen peroxide were used in the oxidation became.

The yield of product was 44.9 g (84.9% of theory)

M.p. 100-102 ^° C

SulEenamide content 99.0% by weight insoluble remainder 0.10% by weight.

Claims (4)

Expectations M .J Process for the preparation of N-Cyclohexylbenzothiazole-2-sulfenamide of formula I. C - S - NH • - C H (I) by reaction of 2-mercaptobenzothiazole and cyclohexylamine with an oxidizing agent, marked by (A) Reaction of 2-mercaptobenzothiazole with excess cyclohexylamine in a molar ratio of 1.5 to 5 mol of cyclohexylamine to 1 mol of 2-mercaptobenzothiazole, (b) oxidizing the resulting solution of the cyclohexylamine salt of 2-mercaptobenzothiazole with sodium hypochlorite or hydrogen peroxide at 20 to 70 ⁰ C. and (c) Separation of the by-products of the oxidation. 2. The method according to claim 1, characterized in that in the reaction (a) a molar ratio of cyclohexyl 233- (S9924) -SF-Bk amine to 2-mercaptobenzothiazole of 2.5: 1 is applied. 3. The method according to claim 1 or 2, characterized in that the oxidation (b) is carried out ^{at 45 0C.} 4. The method according to any one of claims 1 to 3, characterized in that that the starting product is a crude obtained by reacting aniline, carbon disulfide and sulfur 2-mercaptobenzothiazole, which may have been freed of volatile components by blowing through with an inert gas, is used will.